This bibliography contains references to the geologic literature on the State of Minnesota issued from 1981 through 1985, as well as omissions from the previous two bibliographies of Minnesota geology: Bulletin 34 (published in 1951), with coverage through 1950; and Bulletin 46 (published in 1981), with coverage for 1951-1980. The references in the bibliography section cover most geologic topics but exclude those confined to the last 10,000 years, to surface hydrology, and to mining and metallurgy. Most unpublished maps and reports were excluded from this bibliography, because they are not readily available to users. Notable exceptions are theses and dissertations and open-file reports issued in established and accessible series, such as the U.S. Geological Survey's Open-File Report series. An effort was made in the bibliography section to preserve the spelling, capitalization, and punctuation of the original sources; usage in the index reflects current Minnesota Geological Survey style. The last bibliography, Bulletin 46, covered 30 years. Bulletin 47 covers only 5 years, but contains nearly 1,100 references, more than half the number in its predecessor. Much of this inflation may reflect the increased number of abstracts published in recent years. The next bibliography (for 1986-1990) will differentiate between abstracts and more substantive work. The index section, with a few minor changes, closely follows the design of the index in Bulletin 46. It has in one alphabetical listing topical (Ground Water; Petrology; Sedimentation), geographic (Mesabi range; Lake County; Southwestern Minnesota), lithostratigraphic (Duluth Complex; Lake Vermilion Formation), and chronostratigraphic (Paleozoic; Quaternary) indexing. Care was taken to index references to the closest applicable index classifications. For this reason, users of the index are encouraged to search flexibly, to check both broader and narrower index classifications. For example, someone wanting references for Aitkin County may also wish to search a narrower index classification-Cuyuna range, as well as the broader East-central Minnesota. The increased number of cross references in this index should help users with this type of search. Several of the Survey staff were especially helpful in the preparation of the index, and also reviewed the entries in their respective fields: M.J.P. Kuhns and S.J. Mills (economic geology and Duluth Complex); P.L. McSwiggen (petrology and uranium); H.C. Hobbs (glacial geology); and D.J. Bergstrom (Paleozoic rocks and Sioux Quartzite). V. W. Chandler reviewed the geophysics entries; D.R. Setterholm, Cretaceous rocks; R.S. Lively, geochemistry and geochronology; and M.C. Hoyer, ATES. Linda McDonald typed and updated the bibliography through most of its existence. Denise Fletcher typed the index and inserted the typesetting codes. J. F. Splettstoesser proofread the final typescript.